COVID-19 Pandemic Quarantines and Mental Health Among Adolescents in Norway

This cohort study examines the association of mental health and the public health measures and quarantine experiences during the COVID-19 pandemic among Norwegian adolescents.


Introduction
Adolescence represents a transitional period, in which some individuals experience the emergence of mental health disorders, such as anxiety, depression, or eating disorders, 1 with a typical age of onset between 12 to 25 years. 2For example, the period includes developmental changes in cognitive and socioemotional regulation mechanisms that influence decision-making, peer relationships, and well-being. 3,4On March 12, 2020, in response to the COVID-19 pandemic, the Norwegian government implemented several public health measures.These included school closures, stay-athome mandates, and travel restrictions.Although these public measures reduced the spread of the COVID-19 virus, the cessation of after-school activities 5 and isolation from friends 6 could pose threats to adolescent mental health.
In addition to a general trend of increasing mental health problems among young people during the last decades, [7][8][9] numerous studies [10][11][12][13][14] have reported an increase in symptoms of anxiety and depression during the pandemic compared with prepandemic levels, as summarized in a recent meta-analysis based on 53 longitudinal studies. 15Girls tend to show worse mental health during the pandemic compared with boys, 16 and research also points to factors, such as older age, 17,18 lower parental education 19,20 and preexisting mental health problems, 21 as possible vulnerability factors.
Although studies have investigated the associations of restrictive public health measures 22 and quarantine 23,24 with mental health during the COVID-19 pandemic, there is a lack of evidence from adolescent samples.Moreover, except for studies 23,25 suggesting that girls had a worse experience during quarantine than boys, few studies have investigated how individual-level characteristics are associated with mental health outcomes following the implementation of public health measures.Knowledge of potential adverse effects is crucial for policy makers to consider when introducing public health measures to limit spread of communicable diseases in the future.For instance, considering the varying risks and impacts across different people, quarantine measures might be adjusted so that they are not mandatory for vulnerable groups.
It is hard to disentangle the role of the COVID-19 pandemic from the increase in mental health problems among adolescents, which were already on the rise.However, while the pandemic impacted everyone, the stringency of restrictions varied over time.In this study, we used a national restriction stringency index, capturing daily data from April 2020 to February 2021, to investigate how changes in public health measures corresponded with adolescent mental distress.By capturing variance in restrictions, we provide insight into a possible direct mechanism of the pandemic.We further examined the association of recent quarantine and quarantine frequency with mental distress.Subsequently, we explored whether vulnerability factors, such as female sex, higher age, low parental education, prepandemic mental health problems, and genetic liability for mental health conditions, might moderate these associations.

Study Design and Sample
Between March 2020 and February 2021, participants aged 16 to 18 years enrolled in the Norwegian Mother, Father, and Child Cohort Study (MoBa) were invited to complete biweekly COVID-19 surveys.
Six of these included a measure of mental distress (Figure 1).MoBa is a population-based pregnancy cohort study conducted by the Norwegian Institute of Public Health. 26,27 fathers.Blood samples were collected from the umbilical cord during delivery. 28Genotype data were quality-controlled using the MoBa PsychGen pipeline. 29Linked data from the Norwegian Patient Registry provided diagnostic information from specialist health care from 2008 to 2020 using the

International Statistical Classification of Diseases and Related Health Problems, Tenth Revision
(ICD-10) codes. 30

Outcome
Mental distress was measured by the 5-item version of the Hopkin's Symptom Checklist (SCL-5). 33e SCL-5 consists of 2 items tapping anxiety and 3 tapping depression symptoms.

Exposure
The stringency of public health measure was extracted from the Oxford COVID-19 Government Response Tracker, 34 which combines information from 9 metrics, including closures of schools, workplaces and public transport, cancellation of public events, and international travel controls.The index was scored from 0 to 100, with higher score indicating stricter measures.Scores were matched to each SCL-5 report according to the response date.
From March 2020, the Norwegian government mandated a 14-day quarantine for those returning from travel abroad or who had been in contact with confirmed COVID-19 cases.The first couple of weeks with lockdown did not include mandated quarantine, just a recommendation to stay at home.During quarantine, individuals had to stay at home but going outside and necessary

Statistical Analyses
We ran 11 linear mixed-effect models (M0-M10) (eTable 1 in Supplement 1) using the lme4 package 35 in R version 4.1.2(R Project for Statistical Computing) 36 with RStudio. 37We included participants with between 1 and 6 responses to SCL-5 in multilevel models using restricted information maximum likelihood estimation.All models have a hierarchical structure, estimating parameters at 2 levels, allowing us to investigate variance between (level 2) and within individuals (level 1).On level 1, we include variables that can vary across observations (eg, time, stringency).On level 2, we include variables related to the individual (eg, sex, prepandemic anxiety or depression).Nested models were compared pairwise using the analysis of variance function (anova) from the R stats package. 36We validated the model fit by comparing variance explained using marginal and conditional pseudo-R-squared values. 38e baseline model (M0) included a random intercept of the participants' identification number to specify that there were repeated SCL-5 measures for each participant.We ran 2 nested models to estimate the association between public health measures and mental distress.In the first model (M1), we included stringency index and time at level 1 (ie, as fixed effects).We compared the fit of M1 with M0 to assess whether stringency and time were associated with mental distress (ie, testing whether additional terms in M1 explained a significant proportion of the residual variance from M0).In the second model (M2), we also included stringency index at level 2 (ie, as a random slope).This allowed participants to have different linear effects associated with the stringency index accounting for potential unexplained between-individual variance.We then compared the fit of M2 with M1 to assess whether the trajectories differed sufficiently in response to changes in the stringency index.
From the best-fitting model (M1 vs M2) we used the significance (α = .05) of the estimated fixed effect of the stringency index as the basis of the inference for our first hypothesis.For supplementary analyses, we included 2 additional possible moderators reported by a subsample at age 14 years.Prepandemic mental distress and eating problems into our previously specified models.In supplementary (S) models, we added self-reported prepandemic measures as fixed effects and interaction terms with stringency (M-S1-S2), recent quarantine (M-S3-S4), and frequent quarantine (M-S5-S6).
All nested models were run using the same sample.We compared descriptive characteristics across samples: (1) all MoBa participants aged 16 to 18 years, (2) sample in M1 to M4, (3) sample in M5 to M10, and (4) sample in S1 to S6.
To correct for multiple testing across 2 different quarantine measures we used Bonferroni correction to adjust the α level (α = .025,found by .05/2).We used maximum likelihood estimation for analysis of variance comparisons.Data were analyzed from October 2022 to October 2023.
Statistical significance was set at P < .05,and all tests were 2-sided.

Results
This from September to October 2020 (Figure 1).Descriptive characteristics are presented in Table 1.

Public Health Measures
Including the stringency index as a fixed effect (M1) provided a better fit to our data compared with the baseline model (M0).M2, with a random slope for stringency, explained additional 3.2% of the variance.Including covariates (M3) further improved the fit to our data.Based on M3, higher stringency (β = 0.18; SE, 0.02; P < .001)and time (β = 0.13; SE, 0.02; P < .001)were associated with increased mental distress (Figure 2).All M3 parameter estimates can be found in eTable 2 in Supplement 1. Adding interaction terms (M4) did not improve the fit to our data (eTable 3 in Supplement 1).For supplementary models including self-reported prepandemic measures from a smaller sample, the model without interaction terms was best fitting (eTable 4 and 5 in Supplement 1).

Recent Quarantine
Including covariates (M6) improved the fit of the model estimating associations between recent quarantine and mental distress (M5) but adding interaction terms (M7) did not.In the best-fitting model (M6) adolescents who had been quarantined reported more mental distress (β = 0.11; SE, 0.02; P < .001)(Table 2).Parameter estimates are shown in Table 3.For supplementary models including prepandemic measures, the model without interaction terms was the best fitting (eTable 6 to 7 in Supplement 1).

Quarantine Frequency
Including covariates (M9) improved the fit of the model estimating associations between quarantine frequency and mental distress (M8

Discussion
In this longitudinal cohort study, stricter public health measures during the COVID-19 pandemic were associated with adolescent mental distress.Contrary to expected, this association was not moderated by sex, age, prepandemic anxiety or depression, parental education, or genetic liability for mental health conditions.Adolescents who had recently experienced quarantine reported more mental distress, and there was a dose-response association between the number of times quarantined and mental distress.This association was more pronounced among 16-year-olds, those with parents with lower education, and adolescents with a lower depression PGS.1][12] A meta-analysis 22 found a linear association between the stringency of Aligning with previous research, 23,24 we found that both recent and frequent quarantine were associated with mental distress.Association of time was halved when frequency of quarantine was added to the model, indicating that much of the association with time was driven by participants being quarantined.Elevated mental distress during strict public health measures and quarantine could be due to several mechanisms.Social distancing measures can disrupt social connectedness with friends and grandparents, relationships shown to be important for adolescent well-being. 40duced in-person social interactions and more time spent indoors may increase feelings of loneliness and impact mental health. 6The public health measures can also lead to uncertainty, financial hardships, break-up of daily routines, and changes in dietary and sleep patterns, which are factors associated with adolescent mental distress. 23,41Physical activity is associated with mental health 42 and the lack of organized sports might also have contributed to the association.Strict public health measures and quarantine often followed times of rising COVID-19 cases.Therefore, there is a possibly that the associations reported in our study reflects fears associated with this (eg, of infection or death of self or loved ones).
Adolescents with parents with lower education showed a steeper increase in mental distress with frequent quarantine, highlighting the possible role of socioeconomic disparity on adolescents' well-being.Several factors could contribute to this, such as parental income loss or more confined living arrangements, possibly intensifying stress among adolescents when quarantined.
As expected, genetic liability to mental disorders was positively associated with mental distress, but only for the depression PGS.Regarding interaction effects, we found that adolescents with lower depression PGS showed a steeper increase in mental distress with frequent quarantine.Social isolation might be linked to more distress in those not generally distressed, perhaps due to different coping skills and experiences.Additionally, the social network of those with low depression liability might have been stronger and more affected by the COVID-19 pandemic.Adolescents with high PGS may have struggled more before the pandemic (eg, with low social contact, or by being bullied), and some may have experienced a relief by having fewer social or leisure time obligations. 43Our findings aligned with studies showing that adolescents with prepandemic psychiatric symptoms showed an decrease in symptoms 43 and that children with preexisting mental health disorders were less in contact with health care services during the pandemic. 44

Limitations
This study has limitations.First, MoBa has a 41% initial response rate and predominantly consists of well-educated, healthy families. 45Approximately 50% of their children participated in the COVID-19 data collections, and it is not known how well they represent the general adolescent population in Norway.Second, participation dropped from 51% to 17% throughout the 6 data collections, potentially causing selective attrition.However, comparing characteristics of our analytic samples to all adolescents invited did not indicate important differences.Third, observational data limits causal inference.However, the COVID-19 pandemic settings allowed for a natural experiment.The varying intensity of public health measures across time introduced exogenous variation.Fourth, some adolescents might have received mental health services during the pandemic possibly relieving mental distress.Fifth, while the β coefficients are generally small, it is important to consider the broader context in which these associations occur.In the global population, even small shifts in the normal distribution can translate into significant public health implications. 46Sixth, some participants may have interpreted the question about quarantine and isolation as also including voluntary isolation.Adolescents choosing to isolate voluntarily might also score higher on the distress scale.However, we do not believe this to be a major issue, both due to how these governmental measures were communicated in Norway, and due to the low frequency of quarantine and isolation in our sample.Seventh, only 22% reported ever being quarantined possibly limiting the generalizability to countries where quarantine was more prevalent.Future research should investigate regional and country differences in public health measures.

Conclusion
These findings suggest that public health measures and quarantine experiences were associated with adolescent mental distress.In general, these associations were not moderated by vulnerability factors, except for the association with the frequency of quarantine.

Figure 2 .
Figure 2. Multilevel Model Main Effect Estimates for Time, Stringency Level, and Quarantine

Participants were recruited JAMA Network Open | Public Health COVID
-19Pandemic Quarantines and Mental Health Among Adolescents in Norway JAMA Network Open.2024;7(7):e2422189. doi:10.1001/jamanetworkopen.2024.22189(Reprinted) July 12, 2024 2/13 Downloaded from jamanetwork.comby guest on 07/15/2024 from all over Norway from 1999 to 2008.The women consented to participation in 41% of the pregnancies.The cohort includes approximately 114 500 children, 95 200 mothers, and 75 200 Data from the Payment of Health Reimbursements Database contain codes from the International Classification of Primary Care-2 31 between 2006 to 2020.Information about parental education was attained from Statistics Norway.The establishment and initial data collection of MoBa were based on a license from the Norwegian Data Protection Agency and approval from The Regional Committees for Medical and Health Research Ethics (REK).The MoBa cohort is currently regulated by the Norwegian Health Registry Act.The current study was approved by REK.This longitudinal cohort study followed the study includes 7787 adolescents (4473 female [57%]; mean [SD] age, 17.0 [0.6] years).Most participants (5342 [69%]) were 17 years old, 3987 (51%) responded to SCL-5 at least 3 times, and 1730 (22%) had experienced quarantine.The mean (SD) SCL-5 score was 1.53 (0.56) with 1242 (16%) scoring above the established cut-off of 2.0. 39The mean (SD) stringency level during the first pandemic year was 51.8 (14.3), with the highest level at 79.6 in April 2020 and the lowest level at 32.4

Table 1 .
Sample Selection and Descriptive Characteristics a or anxiety symptoms.However, this review primarily focused on adult participants and included only a few smaller adolescent samples (ie, less than 300 adolescents).

Table 2 .
Model Fit Comparison of Models 5 to Model 10 a Abbreviations: AIC, Akaike information criterion; BIC, bayesian information criterion; NA, not applicable.a Model comparison using analysis of variance.The variable time was added to each model.

Table 3 .
Main Outcomes and Interactions of Quarantine on Mental Distress Prepandemic anxiety or depression includes 1 of the following diagnostic codes from International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ie, F32, F33, F34, F40, F41, F93, or F94) or International Classification of Primary Care-2 (ie, P74, P76, or P79).
a JAMA Network Open.2024;7(7):e2422189.doi:10.1001/jamanetworkopen.2024.22189(Reprinted) July 12, 2024 8/13 Downloaded from jamanetwork.comby guest on 07/15/2024 Younger adolescents, those with parents with lower education, and those with lower genetic risk for depression showed more mental distress with repeated quarantines.Insight into how public health measures are associated with adolescent mental health during the COVID-19 pandemic is critical to advance our knowledge and inform policy decisions in preparation for future global public health crises.-19 Pandemic Quarantines and Mental Health Among Adolescents in Norway 46.Carey EG, Ridler I, Ford TJ, Stringaris A. Editorial perspective: when is a 'small effect' actually large and impactful?J Child Psychol Psychiatry.2023;64(11):1643-1647.doi:10.1111/jcpp.13817Model Equations for M0 to M10 eTable 2. Multilevel Model Estimates From Models 1 to 3 eTable 3. Model Fit Comparison-Stringency Index and Mental Distress eTable 4. Model Fit Comparison-Stringency Index and Mental Distress Including Self-Reported Prepandemic Measures eTable 5. Multilevel Model Estimates From Model S1 eTable 6. Model Fit Comparison-Including Self-Reported Prepandemic Measures eTable 7. Main Effects and Interaction Effects of Quarantine on Mental Distress Including Self-Reported Prepandemic Measures in Supplementary Analyses eReferences. COVID